The autoflow package hard wraps the lines, not soft wraps. The difference between hard wrapping and soft wrapping is that hard wrapping inserts an actual newline character into the text. Soft wrapping just wraps the text visually without changing the text content in any way.

Could you be more specific as to what you mean by “justify”? Do you mean something that inserts spaces into the text so that every line in a paragraph except the last goes up to the full configured width?